Many laminates are prepared that include a low-friction layer. In many instances, low-friction layers include materials such as polytetrafluoroethylene or high density polyethylene. While these low-friction layers are technologically useful against contact surfaces, they often present problems in the manufacture of laminates inasmuch as it can be difficult to adhere other materials thereto.
For example, many pieces of furniture, especially chairs, include one or more sliders, which are devices affixed to furniture at a location where the furniture contacts the floor. For example, legs of chairs often include small discs affixed at their bottom that allow the chair to slide across the floor.
Technologically useful furniture sliders exhibit several advantageous physical and mechanical characteristics. First, the surface of the slider that contacts the floor desirably has a low coefficient of friction and high abrasion resistance. Also, sliders desirably have a low compression set so that they can recover after bearing a load. Further, it is desirable that the sliders provide some degree of damping so that the slider will absorb mechanical energy that may be created as furniture slides over a surface or floor.
Materials such as polytetrafluoroethylene and high density polyethylene can have a low coefficient of friction and high abrasion resistance and are often used in the manufacture of furniture sliders. Unfortunately, these materials often do not provide advantageous damping, and their compression set is often not desirable for this use.
As a result, it is common for furniture sliders to include multiple layers of materials; i.e., they are often laminates. These laminates include a first layer that includes a material having a low coefficient of friction and high abrasion resistance such as polytetrafluoroethylene, and a second layer that includes an elastomeric material that has low compression set and the ability to dampen vibrational energy.
The manufacture of these laminates, however, is often problematic. In particular, because many elastomeric materials are thermosets, the elastomeric portion of the laminate is often cast onto a substrate that includes a material such as polytetrafluoroethylene. As those skilled in the art appreciate, the casting of the elastomeric layer can often entail time-consuming and intricate processes. Further problems are encountered in that materials that exhibit a low coefficient friction and high abrasion resistance often do not bond well to other materials. As a result, the formation of a laminate can be problematic.
Thermoplastic vulcanizates are thermoplastic elastomers. In other words, thermoplastic vulcanizates exhibit many of the properties of thermoset rubbers, yet they are processable as thermoplastics. As a result, they offer a unique processing advantage over the use of thermoset elastomers. Indeed, they could offer an advantage in the manufacture of laminates including furniture sliders because casting processes could be eliminated.
Unfortunately, thermoplastic vulcanizates known heretofore in the art have not proven to be technologically useful in the manufacture of furniture slider laminates because adhesion to materials such as polytetrafluoroethylene has not been adequate for furniture slider applications. This is true despite the fact that thermoplastic vulcanizates exist that demonstrate technologically useful adhesion to a number of substrates.